In a particular application, the dispensing system is intended to be provided on bottles used in perfumery, in cosmetics or for pharmaceutical treatments. Indeed, this type of bottle contains a product which is returned by a dispensing system comprising a device for sampling under pressure of said product, said system being actuated by a push-button in order to allow for the spraying of the product. In particular, the system for sampling comprises a pump or a valve with manual actuation by the intermediary of the push-button.
Such push-buttons are conventionally carried out in two portions: an actuator body and a spray nozzle for the product which are associated together to form a vortex unit comprising a vortex chamber provided with a dispensing orifice as well as with at least one supply channel of said chamber.
In particular, the supply channels exit tangentially in the vortex chamber which is cylindrical of revolution in order to rotate the product very rapidly, the dispensing orifice having a reduced diameter in relation to that of said chamber so that the product in rotation escapes through said orifice with a speed that is sufficient to be broken up into droplets forming the aerosol.
However, as this breaking up takes place in an uncontrolled manner, the aerosol is constituted of droplets of highly varied size. For example, for a pump or a valve supplying a push-button with a flow of alcohol under a pressure of 5 bars, and an outlet orifice of 0.3 mm, the aerosol is commonly constituted of droplets of a diameter between 5 μm and 300 μm.
However, the large droplets are heavier than the smallest ones and follow a different dispensing trajectory, which can cause indelible stains in the case of perfumes. Also, the small droplets are the lightest and can be inhaled, which may be the objective sought in the case of medications, but which can be an undesirable effect in the case of toxic products. Furthermore, in the case of medications which must be dispensed according to a precise dosage, the location of application, for example inside the respiratory system, depends on the size of the droplets, and the high disparity of sizes misrepresents the treatment.
Moreover, the size of the droplets coming from a vortex chamber depends in part on the force and on the speed with which the user actuates the pump by pressing on the push-button with his finger, as the induced pressure depends on this.
Furthermore, in particular due to the effects of the centrifugal force at the outlet of the vortex chamber, the aerosol has a tendency to be hollow with a substantially tapered shell which is constituted of most of the droplets although there are few inside the cone. In particular, this distribution of droplets can be detrimental for dermal applications.
It is known moreover, in particular from document FR-2 915 470, a push-button comprising a dispensing chamber which is provided with channels each converging towards an outlet orifice, said converging channels being arranged in order to allow for the impaction of the streams of product dispensed by said orifices. As such, during the impaction of the streams dispensed at high speed, an aerosol is formed without having recourse to a vortex chamber.
However, to produce such an aerosol by satisfactorily controlling the calibration and the spatial distribution of the droplets, it is necessary to form identical streams and of which the convergence is perfect, which is very difficult to carry out industrially at the interface between the actuator body and the nozzle mounted in said body. This results in that the streams can cross without impacting one another or in impacting one another only partially, which degrades the calibration and the spatial distribution of the droplets formed.
Moreover, the supply of the converging conduits or of the vortex chamber according to prior art does not allow for a breaking up of the dose of product to be dispensed, i.e. to return only a portion of the dose provided by the pump. Indeed, the travel of the pressing of the push-button is carried out too quickly, in particular by a magnitude of 0.2 seconds for 120 μl, to be able to be interrupted by the user.